The invention concerns a foldable data support with a contactless chip. It therefore concerns a foldable electronic entity including a contactless chip integrated into a foldable support, such as a passport, a driver's license or any other identity document that a bearer may be required to show during identity checks; it also concerns foldable chip cards for banking applications in particular.
In fact, integrating into a security document, in practice carrying printed data intended to enable an identity check, a contactless chip, i.e. a microprocessor integrated circuit intended to communicate with the external environment by means of an antenna, to enable contactless exchange of information between the document and an external checking station, has already been proposed. This can enable the exchange of data more rich in information than printed characters or even a photograph, such as biometric data, and where appropriate enable verification of the compatibility of the printed data and the stored data so as to detect any attempt to corrupt the printed data.
However, this principle of contactless reading of the data contained in the integrated circuit comes up against the understandable misgiving that this data could be read without the bearer's knowledge by systems that might not be authorized.
Solutions have been proposed for preventing any such unauthorized reading, for example in the document WO2005/045754, by identifying two reference positions of the document, for example the “open” and “closed” positions, and providing for reading of the data to be possible only in one or the other of those positions, or between these two positions. To this end, the integrated circuit is connected to at least one element for coupling it to the external environment, which element is able or unable, depending on the configuration of the security document, to exchange information with the external environment. Thus the document cited above describes a solution in which the coupling element is an antenna produced on two sheets: depending on the geometry of the antenna and on the instantaneous configuration of the document, the integrated circuit detects an electromagnetic field or fails to detect it. In a first embodiment, if the antenna has turns each of which is produced in part on each of said sheets, that antenna enables exchange when the document is open (the turns have a maximum exchange area), whereas, when the document is closed, the halves of each turn are superposed so that they conjointly define a null area, preventing any exchange with the external environment. A converse situation is obtained if the antenna is produced in the shape of an 8, with the antenna tracks crossing over in line with the fold line between the sheets: in this configuration, exchange is possible only when the document is closed. The document cited above further describes solutions involving capacitive type coupling elements.
A similar solution is described in the document DE-19721057, in the case of foldable chip cards.
Clearly such solutions offer only moderate protection against unauthorized reading, given that it remains possible to exchange information with the foldable data support by sufficiently increasing the electromagnetic power radiated in the vicinity of the data support.